1. Technical Field
The present disclosure relates to a roll-suppression device for an offshore structure and, more particularly, to a roll-suppression device for an offshore structure that enables enlargement of a width of a damping plate for suppressing roll of the offshore structure in order to maximize the effect of suppressing the roll and is configured to eliminate a risk of collision of the damping plate having the enlarged width with other ships during shuttle docking or ship-to-ship operation. Further, this device has a detachable structure so as to enable a building operation within a dock or a outfitting operation at shore.
2. Description of the Related Art
In general, an offshore structure is shaped like a ship or a barge, such as floating production storage offloading (FPSO), liquefied natural gas floating production storage offloading (LNG FPSO), floating storage and re-gasification unit (FSRU), etc., which moves in various directions by wind, seawater flow or the like. Among such motions of the offshore structure, rolling has a much smaller damping coefficient than motion in other directions such as pitching, yawing or the like, thereby causing a large rolling motion even on a benign sea.
For the sake of stability and working efficiency on the sea, the offshore structure has generally used a bilge-keel to reduce rolling.
The bilge-keel for reducing rolling, wherein a ship or the like rocks from side to side, is longitudinally attached to left and right bilge strakes, starboards and/or ports of a hull, where the bottom and lateral walls of the hull meet, in a longitudinal direction of the hull. A conventional offshore structure employs the bilge-keel to reduce rolling, but the bilge-keel is not particularly effective at reducing rolling, since it cannot be designed beyond the bilge radius, lateral side and bottom of the offshore structure due to various risks.
In addition, not only do devices for actively suppressing roll of the offshore structure, i.e., an anti-roll tank, a fin stabilizer, etc. have a complicated structure, but also there is no example of practical application to the offshore structure due to issues in maintenance, effect, etc. Moreover, a step, a skirt and the like are considered in light of a large bilge-keel, but entail a serious risk during shuttle docking or ship-to-ship offloading, since they are directly mounted to a base line.